This protocol is designed to access both acute and chronic effects of the calcium channel antagonist, nifedipine, on the hypothalamic- pituitary-adrenal (HPA) axis in patients with cogenital adrenal hyperplasia (CAH). The trial is composed of 3 phases and will involve a double-blind, placebo controlled parallel design. The goal of Phase I is to examine the ability of nifedipine vs. placebo to decrease adrenocorticotropic hormone (ACTH) levels, as well as to begin to assess the dose-dependency of nifedipine effects. The goal of Phase II is to evaluate the long-term effects of nifedipine; that is, can attenuation of ACTH release by nifedipine permit a decrease in the dosage of glucocorticoid needed to supress the HPA axis ? such a decrease would, in turn, reduce the deleterious effects of glucocorticoid treatment in CAH.